A semiconductor device such as an ID chip or an IC card capable of wirelessly communicating data has been put into practical use in various fields, and is expected to further expand its market as a new type of communication information terminal. The ID chip is also called a wireless tag, an RFID (Radio Frequency Identification) tag, or an IC tag. The ID chip and the IC card that are in practical use today each has an antenna and an integrated circuit formed by using a semiconductor substrate.
The ID chip or the IC card can communicate with a reader/writer via radio waves. Specifically, an integrated circuit operates using an AC voltage generated in an antenna by radio waves emitted from the reader/writer and a signal outputted from the integrated circuit is used for load modulation of the antenna, thereby a signal can be transmitted to the reader/writer.